Saturday, 30 August 2008

There's more than one way to pick apart the fabric of space and time. You can dig an enormous hole in the ground, fill it with enormous amounts of cash, and send particles screaming to their deaths inside the eyes of giant robots in search of fundamental truth about how gravity works.

Which is nice.

Or you can quietly sit in a quiet corner of a quiet lab, making simple observations over time of a basic physical phenomenon, and then utter the classic call to arms of scientific revolution: 'Hmm. That's odd.'

There are a couple of outstanding cases of this on the books already - the Flyby Anomaly and the Pioneer Anomaly. In both cases, spacecraft experience tiny accelerations that cheerfully resist explanation. In both cases, the effects are so small and ruling out experimental error so difficult that the anomalies are still pretty much curiosities. A small conference here, a few papers there, but nobody's betting their careers on them.

That may not be true for the latest waxy lump of weirdness to fall out of the lughole of fundamental physics onto the pillow of public scrutiny. The raw data dates from the 80s, where two independent teams in the US and Germany recorded the radioactive decay rate of silicon and radium isotopes over many years.

Outside some very specific conditions, radioactive decay is considered one of the basic random events in the universe, triggered by quantum fluctuations in spacetime. These are among the most significant findings of modern physics, and absolutely essential to our current picture of how things work. Radiation happens when a nucleus's component parts - neutrons and protons - are tipped from one stable relationship to another at lower energy, resulting in the expulsion of the spare energy as mass or photons. Only vacuum fluctuations can cause this tipping.

The experimental results of the long-term tests, however, reveal periodicity in the decay rates. In other words, some sort of signal was imposed on the decay process - a result more difficult to believe than the stars spontaneously rearranging themselves into a picture of Albert Einstein. But the experiments were impeccable.

Now, a paper from researchers in the US points out that the variations in the decay rate correspond very closely to the seasonal change in the distance between the Earth and the Sun - with some possible link to solar activity. They suggest two possible mechanisms, one that the sun has a field that affects a certain fundamental physical constant, the other that there's an interaction between solar neutrinos and nuclei. As neutrinos are those things that don't interact with anything much, and constants are rather supposed to be, well, constant, both are highly suggestive of much more to come. As nobody's started experiments to test any of these ideas, it'll take a while - but they will.

And there's the rather entertaining prospect that what comes out of the LHC will mesh with all the anomalies and provide a whole new way of looking at the world. In fact, it rather has tp. Whatever the future of physics is, it'll be different."